This neuromuscular disease clinical center is an interdisciplinary approach by a group of clinician-investigators to analyze the pathogenesis and pathophysiology of human neuromuscular disease. The center takes advantage of the unique clinical skills and patient population available through the Department of Neurology, research resources available on the campus of the University of Pennsylvania School of Medicine, and the expertise of the investigators in the necessary biochemical, immunochemical, immunohistological, in vivo spectroscopic, and molecular biological techniques. Each of the six projects in the center shares two characteristics: it addresses important questions about the pathogenesis and pathophysiology of human nerve or muscle dysfunction; and each has made significant progress toward answering these questions during the past year.